ML20137Z397

Forwards Request for Addl Info Re External Reactor Vessel Cooling for AP600

ML20137Z397
Person / Time
Site:	05200003
Issue date:	03/10/1997
From:	Joseph Sebrosky NRC (Affiliation Not Assigned)
To:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
References
NUDOCS 9704240140
Download: ML20137Z397 (5)

Text

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. Mr. Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Analysis Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.O. Box 355 1 Pittsburgh,'PA 15230 ' (* )

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SUBJECT:

FOLLOWON QUESTIONS REGARDING EXTERNAL REACTOR VESSEL COOLING FOR THE AP600 ,

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Dear Mr. Liparulo:

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As a result,AP600,4of'its tionofthej the staff review of the# Junethat has. determined 1992 application it needs for design additional informa- certifica-tion. ~ Specifically,4 th'eienclosure to tnis letter contains requests for additional,information concerning external reactor vessel cooling for the )

AP600. % ,

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i- 1 You haveJrequested that. portions'of the information submitted in the

' June =1992, application for design certification be exempt from mandatory public disclosure / While'the staff has not completed its review of your request'in <accordance. with the requi'rements of 10 CFR 2.790, that portion of the submitted information is being withheld from public disclosure pending the staff's final determination. The staff concludes that these followon ques-tions do not.contain those portions of the information for which exemption is

-sought. 'However, the. staff will withhold this letter from public disclosure for 30 calendar days.from the date of this letter to allow Westinghouse the l opportunity to verify the staff's conclusions. If, after that time, you do I not requestf that all or portions of the information in the enclosures be )

withheld from public' disclosure in accordance with 10 CFR 2.790, this letter will be placed in the' Nuclear Regulatory Commission Public Document Room.

If you have any questions regarding this matter, you may contact me at (301).415-1132.

Sincerely, original signed by:

Joseph M. Sebrosky, Project Manager Standardization Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No.52-003

Enclosure:

As stated get";';;;*: M10 FILE CEMEB COPY DISTRIBUTION:

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0FFICE PM:PDST:DRPM m BC:SCSB$5A s D:M:DR'PM l l NAME JSebrosky:s @ 7KudricE( /Y) T TQue DATE 03/ro/97 V' 03/10/97T 03/f0/97 9704240140 970310 4 FICIA RECORD COPY PDR ADOCK 05200003 ,

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Mr. Nicholas J. Liparulo Docket No.52-003 Westinghouse Electric Corporation AP600 cc: Mr. B. A. McIntyre Ms. Cindy L. Haag Advanced Plant Safety & Licensing Advanced Plant Safety & Licensing Westinghouse Electric Corporation Westinghouse Electric Corporation 4

Energy Systems Business Unit Energy Systems Business Unit P.O. Box 355 Box 355 Pittsburgh, PA 15230 Pittsburgh, PA 15230 i Mr. M. D. Beaumont Mr. S. M. Modro

Nuclear and Advanced Technology Division Nuclear Systems Analysis Technologies j Westinghouse Electric Corporation Lockheed Idaho Technologies Company

. One Montrose Metro Post Office Box 1625 11921 Rockville Pike Idaho Falls, ID 83415

'. Suite 350 Rockville, MD 20852

! Enclosure to be distributed to the following addressees after the result of the proprietary evaluation is received from Westinghouse:

Mr. Ronald Simard, Director Ms. Lynn Connor Advanced Reactor Programs DOC-Search Associates l Nuclear Energy Institute Post Office Box 34

1776 Eye Street, N.W. Cabin John, MD 20818

' Suite 300 Washington, DC 20006-3706 Mr. Robert H. Buchholz i

GE Nuclear Energy Mr. James E. Quinn, Projects Manager 175 Curtner Avenue, MC-781

LMR and SBWR Programs San Jose, CA 95125 GE Nuclear Energy

175 Curtner Avenue, M/C 165 Mr. Sterling Franks San Jose, CA 95125 U.S. Department of Energy NE-50

! Barton Z. Cowan, Esq. 19901 Germantown Road 4

Eckert Seamans Cherin & Mellott Germantown, MD 20874 600 Grant Street 42nd Floor Pittsburgh, PA 15219 Mr. Charles Thompson, Nuclear Engineer

AP600 Certification Mr. Frank A. Ross NE-50 U.S. Department of Energy, NE-42 19901 Germantown Road

Office of LWR Safety and Technology Germantown, MD 20874 19901 Germantown Road Germantown, MD 20874 l Mr. Ed Rodwell, Manager

PWR Design Certification i Electric Power Research Institute 3412 Hillview Avenue Palo Alto, CA 94303 i

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Containment Systems and Severe Accident 8 ranch Request for Additional Information Regarding AP600 External Reactor Vessel Cooling (DOE /ID-10460) 480.956 For cases where the metallic layer is contained within the hemi-sphere, Equation 6.9 appears to be in error (the cosine terms become zero for cases where angle theta equals zero). A more appropriate form of the equation is:

sin2 0,Au(Tu-T ) = sin2 0 ii S A ,,(T -Tu) + (H/R)A ,(sinO, i + sinO )(T,-T,m)

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Please clarify what equation is used in the full solution. 1 480.957 Figures 7.4 and 7.6 indicate that the oxide layer height will be 1.5 to 1.6m and the metal layer height will be 0.88 to 1.0m. This would result in the top of the metallic layer being above the hemispherical portion of the vessel. Please justify that the full solution adequately addresses this situation, and provide an estimate of the error introduced by the modelling assumption that metal layer is contained within the hemisphere.

480.958 Please clarify the nomenclature related to T and T . In Equa-4 tion 6.10 and in the discussion on page 6-4,,it app,e,a,rs that T, should be replaced with T If not, please justify why T is j used as a sink temperatur,e'i. is used as a  ;

sink temperature in Equationin6.12. Equation Also,6.10 andsT,h,ow the equation please used to relate T, to T,,, and T g.

480.959 Please clarify the nomenclature and assumptions in the third term of Equation 6.12. In this term, it appears that the molten metal layer emissivity, e, should be replaced with the radiative sink emissivity, c,. Please describe and justify the view factors and area relationships invoked to omit any terms with the vessel emissivity, t yand surface area ratio (S,/S,). It appears that the upper internal structure's heat was assumed to be entirely radiated to the vessel inner wall and that the upper internal structure surface area was assumed to be much smaller than the vessel inner surface area (S, u S,). However, the latter assump-tion contradicts nomenclature shown in Figure 5.1 (S pointing to both the upper internal structure inner surface and I.he vessel inner surface implies that these areas are equal).

480.960 It appears that the coefficient of the fourth terni in Equation E.3 should be 1.35x10-2. Is this a typographical error?

480.961 Please clarify why the ratio (H/R)" 25 is discussed on page 6-3.

The equations used for predicting upward and downward heat trans-fer coefficients (Equations 5.12 and 5.28) don't have an (H/R) term.

Enclosure

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j 480.932 Please describe and justify the assumptions used to obtain Equa-tion 5.41 from Equation 5.35.

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) 480.963 Please indicate the equation used to estimate A in the full model (Information on page 6-4 suggests that a Prandt1 number function, rather than Equation 5-47, was used to evaluate the term, Ay) .

480.964 Please indicate what properties were varied with temperature in Equation 6.11 (the equation suggests that all the thermophysical properties were evaluated at the appropriate film temperature except the thermal conductivity, k). Pleasespecifythevalues used to obtain a single value for A (2764 W/m K) that is applica-

) ble to all directions (see captions for Figures 6.3 and 6.4).

480.965 For the following variables, please: (1) clarify if single values were used, (2) state the values or range of values assumed, and (3) provide the basis for these values: .

- Upper Vessel internal structure internal surface surface area, area, S,5.1 nomenclature)

S, (Figure Upper internal structure thickness, 6,

- Vessel thickness, Upper internal struc6,ture emissivity, (

Upper internal structure thermal conductivity, k, 480.966 In the response to RAI 480.459, it is noted that: (1) the initial core barrel thickness (2 inches) .is assumed for the upper internal structure thickness, (2) the initial vessel thickness (8 inches) and 3 the vessel side wall was assumed for the vessel surface area above the melt (57.4 m thicknesg), was a(ss)umed for the vessel internal surface area. Please demonstrate that results aren't sensitive to values assumed for these parameters. Also, clarify if the area of the upper internal structure surface area and the vessel internal surface area were assumed equal as suggested by Figure 5.1 nomenclature.

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I i-l DISTRIBUTION letter to Mr. Nicholas J. 'Linarulo. Dated: March 10. 1997

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